Volcanoes are Hot Stuff

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Volcanoes are Hot Stuff

• By
• Shana Huffaker And Doreen Snyder
• Modified by Mr. Kennedy

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What is a Volcano?

• Volcano- Areas of earths surface through which
  magma and volcanic gases pass
• Volcano comes from the Roman word Vulcan, which
  means fire
• Magma rises because it is less dense than the
  solid rock around it.

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What are the parts of a Volcano?

1. VENT- the vent is the opening from which lava
   flows. Dust, ash, and rock particles can also be
   thrown out of the vent!

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A lava flow is the area covered by lava as it
pours out of a vent A crater is a bowl-shaped
area that may form at the top of a volcano around
the central vent
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Craters, Calderas, and Lava Plateau

• Crater
• From explosions of material out of the vent and
  the collapse of material back into vent

• Caldera
• Much larger depression that forms when magma
  chamber empties and its roof collapses

• Lava Plateau
• Forms when lava erupts from long cracks, or
  fissures, and spreads out evenly (thousands of km)

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How are volcanoes formed?
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• Deep in the earth it is very hot. It is so hot
  that rocks melt. The melted rock is called
  magma. The magma is lighter than the rocks
  around it so it rises. Sometimes it finds a
  crack or hole in the earths crust and bursts
  through. This is how a volcano begins.

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Why do volcanoes erupt?
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Pressure builds deep in the earth where
the magma is. Suddenly the gases escape and
violently explode. It is kind of like
toothpaste squirting out of a tube when you give
it a hard squeeze.
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What are the different kinds of volcanoes?
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Volcanoes do not all look alike. Their shape
is based on what type of materials they erupt.
There are three main kinds, or shapes, of
volcanoes.
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• 3. Volcanic cone- is the pile of lava, dust,
  ashes, and rock around the vent. It can be found
  in different shapes!

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Types of Volcanoes
Shield volcano
Cinder cone volcano
Composite volcano
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ShieldVolcanoes
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Volcanoes that build up from many slow, steady,
flows of hot lava, are called shield volcanoes.
This kind of volcano is low and broad with gently
sloping sides. They look like a warriors shield.
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Shield Volcano

• Is wide and somewhat flat.
• It forms from a quiet eruption.
• Lava flows out quietly and for great distances.

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Cinder Cone Volcanoes
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Cinder cone volcanoes form when solid rock and
ash shoot up into the air and fall back around
the volcano opening. The cinder cone volcano
has steeply sloped sides.
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Cinder Cone Volcano

• Has tall, very steep sides.
• Has explosive eruptions.
• This eruption produces a lot of cinder and ash.

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Strato or Composite Volcanoes
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Strato volcanoes, also called composite
volcanoes, erupt with molten lava, solid rock,
and ash. The layers pile up much like layers of
cake and frosting. The layers form into
symmetrical cones, and the slopes are steep.
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Composite Volcano

• Form from explosive eruptions.
• Produce a lot of lava and ash.
• Is small, with steep sides.

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Whats inside a volcano?

• Magma Chamber- molten rock that feeds a volcano
• Vents- cracks in the crust
• What is the difference between magma and lava?

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Types of Volcanoes

• Shield Volcano
• Built from layers of lava
• Non-explosive eruptions
• Not very steep, but can be big

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Types of Volcanoes

• Cinder Cone Volcano
• Built from pyroclastic material
• Moderately explosive, short eruptions
• Small in size, steep slopes

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Types of Volcanoes

• Composite Volcanoes
• Most common type
• Explosive eruptions and lava flow
• Built from pyroclastic material AND lava

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What Erupts from a Volcano?
Blocky lava
Lava can be thick or thin.
Pahoehoe
Aa
Pillow lava
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What Erupts from a Volcano?

• Pyroclastic material
• Rock fragments created by eruptions
• magma explodes from volcano and solidifies in the
  air
• existing rock is shattered by powerful eruptions

EXPLOSIVE
Lapilli
Volcanic bombs
Volcanic blocks
Volcanic ash
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How do volcanologists predict eruptions?

• Measuring Small Quakes
• Before eruption, increase in number intensity
• Measuring Slope
• Bulges may form with magma (tiltmeter)
• Measuring Volcanic Gases
• Outflow of volcanic gases
• Sulfur dioxide, carbon dioxide
• Measuring Temperature from Orbit
• Measure changes in temperature over time

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There is much more about volcanoes out there.
Look in books and on the internet . Have Fun!
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• Pictures, Images, and information
  From
• Soames Summerhays/Photo Researchers, Inc.
• Kraft-Explorer/Photo Researchers Inc.
• Masao Hayashi-Dung/Photo Researchers Inc.
• Why Do Volcanoes Blow Their Tops? By Melvin and
  Gilda Berger
• www.usgs.gov/education/learnweb/volcano/index.html